Eumasia venefica, Unnikrishnan & Sobczyk & Jose & Jose, 2023

Unnikrishnan, Usha Ayyath, Sobczyk, Thomas, Jose, Roby Thekkudan & Jose, Joyce, 2023, Eumasia venefica sp. nov. a new species of the subfamily Eumasiinae (Lepidoptera Psychidae) from India with atypical larval ecology, Zootaxa 5352 (4), pp. 521-536 : 523-533

Eumasia venefica sp. nov.

(Figs: 1–11)

Type material. Holotype. ♁, INDIA, Kerala, Nariyampara, Kattappana, Idukki , 9.7424° N, 77.0939° E, 28-x-2022, with larval case, leg. Usha A U.

Paratypes: one female (with larval case), same data as holotype, 19-x-2022, 3 larval cases without pupal exuviae, leg. Usha A U.

Etymology. Larval bags have a ‘witches’ hat’ appearance, a disc-like anterior and a tubular posterior part. The Latin word ‘ veneficus ’ means wizard. As Eumasia is a female term the feminine form of ‘ veneficus ’, ‘ venefica ’, has been used. Hence the name Eumasia venefica .

Description. Holotype ♁ ( Fig. 1 ), Wingspan 8.0– 8.2 mm, body length 3.0– 3.2 mm, forewing length 3.8 mm including fringes, forewing width 1.1 mm, WI 3.4 mm, hindwing length 3.3 mm.

Head. Vertex densely covered with pale golden coloured hairs; the frons has a bilobed tuft of golden hairs. eyes are large, EI 0.76 mm. Antenna thread-like, short cilia on segments, 26 segmented, 1.6 mm long.

Thorax. Covered densely with light brownish scales. Forewings are covered with pale brown and blackish scales. The scales are broad and have 5 pointed apices. Ground colour of the forewing is pale brown and the blackish scales in the forewing form patches and are randomly distributed on the wing surface ( Fig. 3 ). Hindwings are whitish without any spots or patterns and covered with pale golden scales. Wings are lanceolate, apex pointed, outer margin with long brownish fringe hairs. Legs are covered with long pale brownish hairs; the tarsal segments of the legs have darker scales or hairs. Hair brush is seen on the tibia instead of epiphysis. Hind legs are relatively very long ( Fig. 1 ).

Venation. ( Fig. 5a, b ) Nine veins in the forewing, seven veins from the dc forewing. Veins M 1 and R 4 +R 5 are shortly stalked, a median stem divided dc two halves. Veins M 2+3, CuA 1 and CuA 2 are short and parallel to each other. Hindwings are narrow and pointed, have seven veins and vein Sc+R 1 runs parallel to the costal margin. Vein Rs and M 1 are stalked. M 1 and M 2 +M 3 run as a separate vein to termen. CuA 1 and CuA 2 are shortly stalked. Anal veins are very short.

Abdomen. Densely covered with scales, the anterior portion of the abdomen is covered with pale brownish scales and the last abdominal segments and the tip of the abdomen are covered with blackish-brown scales.

Genitalia. ( Fig. 6 a, b ) Elongated, 1 mm in length. Tegumen arched apically. Valva is short and symmetrical, at the apex with short setae. Sacculus distally with some sharp, curved thorns. Vinculum is very long and V-shaped. Saccus long and pointed at the apex. Phallus tubular, with a pointed tip, length 0.8 mm. Gnathos and juxta absent.

Paratype ♀ ( Fig. 2 ). Winged, wingspan 9.0– 9.3 mm, body length 4.2 mm, forewing length 4.5 mm excluding fringes, forewing width 1.3 mm, forewing index 3.4 mm, eyes are large, ocular index 0.93 mm. Antenna thread-like with short cilia on segments. The head and area surrounding the eyes are densely covered with long golden hairs. abdomen is long and stout, pale yellowish thinly covered with scales. Wings are lanceolate and narrow with long fringes. Forewings are densely covered with pale golden-brown scales. Dark brown scales are present and form patches and spots on the forewings. Four dark patches which are vertically arranged on each forewing have been seen. When wings were folded close to the body, the spots on both wings came together to form a median band just below the anterior end ( Fig. 4 ). Hind wings are fully covered with pale whitish shiny scales without any markings. The wing venation is same as in males. Legs are elongated and covered with long shiny white scales. The last abdominal segment has a long hair tuft surrounding the genitalia and a long ovipositor extended outside the last abdominal segment.

Larva: ( Fig. 7 a, b ; 8 ) Larva is pale yellowish, head is dark brown, highly sclerotized without any patches. A mature larva is 4 mm in length.

Larval cases and habitat: Larval cases were found attached to rocks covered with lichens. The larvae actively move on the surface of rocks and feed on lichen parts. The pupal bags are found colonizing as groups during pupation, attaching to each other in the lichen colony on the rocks. The pupal cases exhibit camouflage and are difficult to distinguish from the lichens ( Fig. 12 a, b ). Larval bags have a ‘witches’ hat’ appearance, a disc-like anterior and a tubular posterior part. The cases are built with silk, soil, rock and lichen particles and the colour of the cases resemble the lichen with which they have been associated. The male and female cases have size differences and they form pupal groups mixed with both sexes ( Fig. 10 ). The adult male pupal case has a maximum length of 7 mm and width of 5.5 mm at the anterior end. The female pupal case has a maximum length of 9 mm and width of 6 mm at the anterior end.

Biology. Other species of subfamily Eumasiinae have been previously reported to inhabit rocks and their premises, and feed on the algae and mosses on the rocks ( Saigusa & Sugimoto 2013; Roh & Byun 2016, Roh et al. 2018). Similarly, Eumasia venefica sp. nov. also feeds on the lichens and other materials present on the surface of the rocks.

The larval and pupal case structure is distinct and well-adapted for the protection of pupae during the metamorphosis into the adult. The larvae move on the rock surfaces and feed on the lichen cover. It drags its ‘witches’ hat’ shaped cases along as they move. The anterior wide end of the case covers the larval body while moving and acts as a shield or like an ‘umbrella’ over its body. The larvae directly attach the anterior part of the case during rest and pupation. The outer edges of the wide part are pasted on the rock surface with silken threads and form a ‘cup-shaped’ space anteriorly and this space acts like a brooding chamber or pupation chamber for the development of pupae into adult insects. The exoskeleton and head capsules of larvae after moulting will deposit into this space ( Fig. 11 ). The posterior tube-like case is extended into this space and metamorphosis is completed at this extended tip of the case ( Fig. 9 ). The male-female ratio at emergence was 1:1 (2 each) unlike other species of the region where females outnumbered the males.

Distribution. Larval and pupal cases were collected from Nariyampara of Idukki, Kerala ( Fig. 13 ). The collection site was at an altitude of 960 mASL. Soil Maps of India (1996) describe the soil of the region as ‘Clayey mixed ustic pale humults and rock land (very deep, well-drained, clayey soil on moderately steeply sloping high hills with thin vegetation, with moderate erosion, associated with rock outcrops and deep well-drained gravelly loam soils on gentle slopes). Average temperature is 20°C. Summer temperatures range from 19°C to 29°C and winter temperatures fluctuate between 15°C to 24°C. The Centre for Earth Studies Resource Atlas of Kerala (1994) records average rainfall at Nariyampara was South West Monsoon 150 cm and Northeast Monsoon 40 cm and ‘Other rains’ was reported as 30–50 cm.

DNA barcode and phylogenetic analysis. COI sequencing of the species was done and the sequence has 655 base pairs. The sequence was uploaded to the NCBI GenBank with the accession number OR044899. The BLAST search results of the sequence show 93.59% sequence similarity with Eumasia thomasii (OP302728) from India and 89.88% with Eumasia muscella (LC094210) from Japan.

The tree ( Fig. 14 ) with the highest log likelihood (-1709.54) is shown. The percentage of similarity between each taxon and taxon cluster is shown next to the branches. Eumasia venefica sp. nov. shows the highest relation with Eumasia thomasii from Kerala, India. This cluster shows higher affinity to the branch having E. muscella and E. viridilichenella (both species reported from Asia). Detailed discussion of the eastern and western group of Eumasia following Hättenschwiler (1998) has been presented by Usha et al. (2022b).

Diagnosis. Eumasia venefica sp. nov. differs from E. thomasii ( Usha et al. 2022b) from Kerala, India by wing venation, wingspan and larval case structure. No veins are stalked in E. thomasii , whereas veins R 4+5 and M 1 are shortly stalked in Eumasia venefica sp. nov. The wingspan between male and female Eumasia venefica sp. nov. has a 1 mm difference (M:8–8.2, F: 9–9.3) whereas both sexes in Eumasia thomasii have a lesser difference in wingspan (M: 8–8.2, F: 8–8.8). Eumasia venefica sp. nov. flies in October and November but flights were observed in E. thomasii during January and July. Walker (1964) described E. arenatella with a wingspan of 12.6 mm which is much larger than E. venefica sp. nov. E. arenatella was reported from Eastern Himalayas from an altitude of 5000 ft Meyrick (1910). E. arenatella had six forewing dc veins ( Hättenschwiler 1998) which is one less than E. venefica . Male moth of E. exoria reported from Bengal had a larger wingspan than E. venefica . Venation has not been described. ( Meyrick, 1911, 1919). Flight time of both these species also differed from E. venefica sp. nov. ( Table 2 ). Colour and markings are also different with both E. arenatella and E exoria being much paler. Meyrick (1919) describes E. exoria with “markings dark fuscous; five roundish spots on costa, two in the disc at middle and ¾ (representing stigmata), and several small elongate marks on posterior part of dorsum and termen. Cilia whitish, basal half barred dark fuscous irroration” which is different from E. venefica sp. nov.

E. muscella Saigusa & Sugimoto, 2005 ( Roh et al. 2018) from Japan and South Korea also differ in forewing venation - the veins R 4+5 and M 1, M 2+3 and CuA 1 are stalked in E. muscella .

The genitalia of Eumasia venefica sp. nov is distinct from E. thomasii . The genitalia of E. venefica is longer than E. thomasii . In E. thomasii the tegumen is arched anteriorly while in E. venefica it is arched apically. Valva is elongated in E. thomasi but short in E. venefica . Phallus is longer in E. venefica ( Fig.6 ). The descriptions of two other species of Eumasia from India ( E. exoria Meyrick, 1919 and E. arenatella Walker, 1864 ) do not provide details of genitalia. The overview of 10 described Asian species of Eumasia (Table: 2) shows that the new species has distinct characteristics from other species of the same genus. For nine of these species, the original descriptions are brief and do not allow comparative statements.

Figures

FIGURE 1. Holotype of Eumasia venefica sp. nov.

FIGURE 2. Paratype of Eumasia venefica sp. nov.

FIGURE 3. Male dorsal view.

FIGURE 4. Female dorsal view.

FIGURE 5. a. Forewing venation, b. Hindwing venation, drawing T. Sobczyk.

FIGURE 6. Male genitalia, a. genitalia of Eumasia venefica sp. nov, b. genitalia of Eumasia venefica sp. nov., drawing T. Sobczyk c. genitalia of E. thomasii d. genitalia of E. thomasii, drawing T. Sobczyk.

FIGURE 7. Larva a. dorsal b. ventral.

FIGURE 8. Larva with case.

FIGURE 9. Pupal exuvia at the posterior end of the case.

FIGURE 10. Male and female pupal cases attached to each other.

FIGURE 11. Cup shaped region of the pupal case, head capsules and other remnants seen in this space.

FIGURE 12. Larval habitat; a. Larval case clustering as a colony on lichen covered rock. B. Larva protruding out of the anterior opening of case seen built with lichens.

FIGURE 13. Map showing location of type locality.

FIGURE 14. Phylogenetic tree showing systematic position of E. venefica sp. nov.